The present invention relates to component packaging. More particularly, the present invention relates to a redundant package for isolating optical components (e.g. arrayed waveguide gratings) from external stresses.
Fiber optic communication links have been conventionally employed in long-haul, point-to-point networks with controlled environments at all interface points. Such highly controlled, xe2x80x9ccentral officexe2x80x9d surroundings usually offer relatively benign operating environments (temperature, humidity, mechanical) for components. Consequently, highly functional components could be developed and installed without considering the impact of other, more extreme environments.
Recent technological advances, coupled with increasing bandwidth demand, are rapidly expanding the use of fiber optic components beyond the xe2x80x9ccentral officexe2x80x9d and into potentially harsher environments. For example, dense wavelength division multiplexing (DWDM) enables the transmission of multiple, independent wavelength streams across a single fiber. Predictably, this capability has resulted in the requirement to add or drop these optical channels along the previously untapped long lengths of fiber (and outside of the central office environment) to provide access to the individual wavelength streams. Optical add/drop multiplexers (OADM) are employed for this function, enabled by arrayed waveguide grating (AWG) components for filtering and forwarding individual wavelengths.
In addition to these technological advances, simple market forces are pushing fiber networks beyond central offices and into the diverse terrain of xe2x80x9cmetroxe2x80x9d markets. This ever-increasing need for bandwidth which only fiber can deliver is resulting in the widespread deployment of fiber networks, and their associated components, into the harsher, less environmentally controlled conditions present in the metro market.
The demands placed on component designers now reach far beyond optical performance, and into the realms of thermal and mechanical insulation. Certain qualification standards (e.g. Telcordia) exist for reliability of optical components, and many customers require qualification under these standards. AWGs however are thin, fragile chips with narrow waveguides produced using planar light-wave circuit (PLC) processing techniques. The various processing tolerances required to meet the requisite optical specifications are already very tight, and in fact get tighter as the need to process more and closer channels increases. It is difficult and costly to impose yet additional requirements on the chip process in the form of advanced materials, processing techniques, etc. to satisfy the harsher environmental standards discussed above.
Environmentally secure packages therefore now play a vital role in the widespread commercialization of these devices. Without adequate packaging, components such as AWGs, with their highly unique and useful functions, would be relegated to laboratory environments only.
What is required, therefore, are advanced packaging techniques to enable the widespread use of otherwise fragile optical components in diverse and often stressful environments.
Accordingly, the present invention relates to a package for an optical component comprising: a package base; a heater affixed to the package base, to control the temperature of the optical component, the heater having a coefficient of thermal expansion substantially matched to that of the optical component; sidewalls affixed to the base around the heater and optical component; and a lid affixed over the sidewalls. The optical component is disposed over the heater and in thermal contact therewith.
This package is especially useful if the optical component comprises a planar light-wave circuit (PLC), e.g. an arrayed waveguide grating (AWG), which requires tight temperature control and structural integrity to maintain the integrity of the optical paths.